Biometrics have a number of advantages over security measures which use tokens such as physical keys, and those which are knowledge-based such as password protection. Biometric features cannot be easily stolen, lost, guessed, forgotten, or duplicated. The list of physiological and behavioral biometric characteristics that have so far been developed and implemented is extensive including the face, iris, fingerprint, palm print, hand shape, voice, written signature and gait. These biometrics have drawbacks. For example, fingerprint and palm print are usually frayed; voice, signatures, hand shape and iris images are easily forged; face recognition can be made difficult by occlusions or if the person has undergone a face-lift. Various experiments have shown that biometrics such as fingerprint, iris and face recognition are susceptible to spoofing attacks, that is, the biometric features are copied and used to create artifacts that deceives many biometric devices.
All authentication systems based on biometrics are flawed if they cannot distinguish between a photograph and the live presence of a person. Therefore, a technique of detecting liveness should be done to ensure that input biometric features are not collected from an inanimate object. The aim of liveness detection (or vitality detection as it is sometimes known) is to determine if the biometric data is captured from a legitimate living user physically present before a biometric data acquisition device. Various liveness detection methods have been implemented, for example, perspiration is used for proof of liveness of a fingerprint and iris shrink is used for verifying liveness of an iris. However, these liveness detection methods require complex hardware, or can be easily defeated.
Accordingly, there is a desire for an authentication system and method that ensures that sensed measurements for verifying the identity of a person are not fraudulent.